Process of treating molten metals and alloys with compositions containing lithium and products resulting from such treatments



Patented Aug. 2, 1932 UNITED, STATES PATENT OFFICE HANS OSEORG, OF FBANKFORT-ON-THE-MAIN, GERMANY PROCESS OF TREATING MOLTEN METALS AND ALLOYS WITH COMPOSITIONS CONTAIN- ING- LITHIUM AN D PRODUCTS RESULTING FROM SUCH TREATMENTS No Drawing.

lithium and incorporating it in a molten mass; the second was relatively high loss of lithium due to volatilization and the like; and the third was the relatively high cost of pure lithium. In other words, when lithium or in fact some other metal of the alkali group or alkaline earth group was added to a molten 2o bath of metal these disadvantages were encountered which in many-cases not only counter-balanced any advantages but actually over-balanced any advantages. For instance, in the treating of steel or steel alloys, the temperature of the molten bath was such as to cause a quick volatilization of lithium with theconsequence that the treatment only partly occurred or that an excessive amount 0 lithium had to be used in order to obtain the so desired results. In the same way, in the treatment of copper and copper alloys, the lithium added to treating the molten mass of copper was quickly volatilized from the molten bath and the remainder produced results which were not uniform nor satisfactory. For instance, the .electrical conductivity of copper when treated with lithium metal was sometimes on1y90 to 95% and the fracture as well as the specific gravity were inferior to those usually obtained with the conventional casting methods and procedures employed in the copper industry. In short, the results of treatment of molten metals and alloys with lithium metal or other metals of the alkali group or alkaline earth group alonewere un- Application filed July 12, 1930. Serial No. 467,625.

satisfactory when carried out on an'industrial scale. Various suggestions have been made for remedying the short-comings and disadvantages of the pure lithium treatment, but none, as far as I am aware, has been satisfactory and practical in industrial use.

It is an oi. ect of the present invention to provide a process of treating metals and alloys in their molten state so as to obtain the benefits resulting from lithium treatments without the disadvantages noted hereinabove.

It is a further object of the invention to provide a simple, economical and thoroughly satisfactory process of treating metals and 50 alloys in their molten state with active lithium alloy of a metal of the alkali group or of the alkaline earth group so as to improve the characteristics thereof.

It is another object of my invention to provide a process of treating molten metals and molten alloys with an active lithium-bearing alloy of a metal of the alkali group or the alkaline earth group which is capable of being carried into commercial practice on an- 7 industrial scale in the ferrous and the nonferrous industries and which is also capable f of producing greater effects than provided by the same amount of lithium and the like.

Other objects andadvantages of the invention will become apparent from the following description. Broadly stated, my invention contemplates the treatment of molten metals and alloys with an active lithium-bearing substance in so which the lithium is so bonded that the loss thereof through volatilization and the like is materially reduced. At the same time the lithium bearing substance can function actively -to effect improvements in the properties and qualities of the metallic substance 1 under treatment. I have found that in carrying my invention into practice, that lithium-bearing alloys contaming members of the alkaline or alkaline earth families or of mixtures of the foregoing alloyscan be utilized in the treatment of metals and alloys in their molten state so as to effect improvements in the properties and qualities in the metals or alloys treated.

The following example is given for illustrative purposes and for a better understanding of carrying my invention into practice.

, Example In thevtreatment of iron or' steel, for instance the molten metal is contained in. a suittreating-about 100 parts of molten steel or steel alloys.

The addition of the active'lithium-bearing alloy to'the molten metal is preferably effected, by plunging the selected amount of activej lit ium bearing alloys into the molten material in a crucible by any appropriate means: such as an inverted cup with side openings or ports or the like. By adding the activelithium-bearing alloy to the molten metal in the aforesaid manner, I am able to e'fieotzathorough distribution of the lithium allo y. throughout the molten mass and to effectthe proper treatment of said metal. to

When' iron or;steel;or=-copper or-nickel or alloys-thereof-are treated with one of my active lithium bearin al loys, the molten mass has a betteriflui ty andgconsequently, can be cast very. much better-thanheretofore and gives better and denser. castings. In addition, the physical propertiesof; the iron or steel or metal or alloy treated Tare-improved. For instance, there is an increased hardness and corrosive resistance of the metal thus treated and the finished. product is relatively or practically free from blow holes, oxygen, sulphur and the like. When copper is treated in this maner, it has a better conductivity than when untreated or treated in conventional ways. 7

The lithium thus added as described hereinabove, improves the crystal structure of'the steel; combines with gases, such as oxygen and nitrogen, and also with such detrimental substances as sulphur and phosphorus; increases the fiuidity. of the molten steel and produces denser and sounder casting than produced heretofore. In practice, I prefer in some instances toadd the lithium alloy in a. mass which is surrounded by or coated with iron silicide. By adding the lithium alloy infiprove the properties and qualities there-- tember 6, 1930.

Instead of steel or iron in the examples given above, nickel or alloys thereof or cop- 'per or alloys thereof can be treated by the addition of the lithium alloy to the molten metallic mass. Suflicient lithium-bearing substance is added to the molten mass to give the latter a lithium content up to about 1.0%.

In some instances, I prefer to employ ah alloy of lithium with the metal-or alloy to be treated. For example, if steel is to be treated, I use an active lithium alloy containing iron. In the same way, if nickel isto' be treated, I use a lithium alloy containing nickel. The lithium alloys should preferably have a lithium content of about 50% and should be silicided or reacted with silicon prior to use.

The amount of lithium alloy added to the molten metallic mass depends upon a number of variables asv one skilled in the art will readily understand. For example, the percentage of lithium in the lithium. alloy will determine in part 110w much of thesubs'tance. is to'be used. Then again the amount of impurities and gases in the molten metal or alloy and the improvement to be given to the metal or alloy will also have to be taken into account indetermining the amount of lithium-bearing substance to be used.

It will be observed that the present invenyides pmcess which can be utilized on an [scale to produce successful andsatisfactory results which are acceptable to those skilled in the art.

It will be further observed that the present invention provides a method for theproduction of improved metals and alloys which not only can be carried out on a laboratory scale but which also can carried out on an industrial scale.

It will also be noted that the present invention' provides a process by the use of which the disadvantages inherent in the-sole use of lithium alone or other member of the alone or of other metals of the alkali or alkaline earth groups alone. 1

' Althoug I have herein described specific illustrative examples of my invention which included specific substances, percentages and the like, itis to be'observed that the invention is not to be limited thereto but the scope and spirit thereof is to be determined by the. ap pended claims. For instance, when in the specification and claims I use the term lithium-alkali alloy it is intended to mean lithium alloy of a metal of the alkali group or alkaline earth group.

In the same way, when the term alkali 1 is used, it is intended to refer to and to include sodium, potassium, calcium, strontium, barium and magnesium which are members of the alkali and alkaline earth families and which have atomic weights greater than 20. It is also to be understood that the term alkali covers mixtures ofthe foregoing elements.

What is claimed is: v

1. The process of treating, purifying and scavenging metals and alloys in theirmolten state to improve the properties thereof which comprises-introducing into a bath of a molten metal or alloy, an active lithium-alkali alloy in restricted amounts only-sufiicient to purify, -scavenge and improve the said metal or alloy and insuflicient to remain in the finished'and treated metal or alloy as a dominant compound or constituent thereof.

2. The process of treating, purifying and scavenging metals and alloys in their molten state to improve the propertiesthereof which comprises introducing into a bath of molten metal or alloy an active lithium-alkali alloy in restricted amounts only suflicient to purify, scavenge and improve the said metal or alloy and insuflicient to remain in the finished and treated metal or alloy as a dominant compoundor constituent thereof by. dipping a solid body of an active lithiumalkali alloy into the molten mass or metal to be treated and then stirring the thus treated molten mass to effect-a thorough distribution of said lithium-alkali alloy.

.3. The process of treating, puri ing and scavenging metals and alloys in their molten state to improve the properties thereof which comprises introducing into a bath of molten metal or alloy an active lithium-alkali alloy in restricted amounts only suflicient to purify, scavenge and improverthe said metal or alloy and insuflicient to remain in the finished and treated metal'or alloy as a dominant compound or constituent thereofby adding a briquette containing an active lithium-alkali alloy' to a molten mass 0 in said molten metal or alloy.

4. The process of treating, purifying and scavenging metals and alloys in their molten lithium-calcium alloy to effect purification,

scavenging, and an improvement of the metal or alloy under treatment.

5. The process of treating, puri ing and scavenging metals and alloys in their molten state to improve the properties thereof which comprises introducing into a bath of molten metal or alloy a lithium-calcium alloy in restricted amounts only sufiicient to purify, scavenge and improve the said metal or alloy and insuflicient to remain in the finishedand treated metal or alloy as a dominant compound or constituent thereof by dipping a block of lithium-calcium alloy into the lower portion of a molten mass of the metal or alloy to be treated and distributing said lithium calcium alloy substantially throughout said mass to efl'ect purification, scavenging and an improvement of the metal or alloy under treatment. I 6. The process of treating, purifying and scavenging metals and alloys in their molten state to improve the properties thereof which comprises adding a lithium alloy containing an alkali metal to a molten mass of metal or alloy to be treated in restricted amountsonly suflicient to purify, scavenge and. improve thesaid metal or allo and insuflicient to remain in the finished and treated metal or alloy as a dominant com ound or constituent thereof and stirring sai molten mass to effect a treatment of-the various parts of said,

mass with said lithium alloy'containing an alkali metal. 1

7. The process set forth in claim 6 in which the lithium alloy is a block of lithium-alkali alloy which has its exposed surfaces covered with lithium.

8. The process set forth in claim 6 in which the lithium alloy is a block of lithium-alkali alloy which has its exposed surfaces covered with a metallic silicide.

9, The process of purifying, scavenging and improving high melting point metals and alloys which comprisesintroducing into a molten bath of said metals and/or alloys a lithium-alkali alloy in restricted amounts only sufiicient to purify, scavenge and improve the said inetal or alloy and insuflicient f to remain. in the finished and treated metal or alloy as a dominant compound or constituent thereof.

10. The improved product which comprises a highmeltin point metal or alloy resulting from the purif ymg and scavenging treatment thereof in ai molten state with a lithiumalkali alloy. v

11. The improved productwhich comprises a high melting point metal or alloy re- 5 sulting from the purifying and scavenging treatment thereof in a molten state with a lithium-calcium alloy. i n 4 12. An article of manufacture comprising an improved metal or alloy resulting from the, purifyin and scavenging treatment thereof in a mo ten state with a lithium-alkali alloy in restricted amounts, only sufiicient to purify, scavenge and improve the said metal or alloyand insuflicient to remain in the finished and treated metal or alloy'as a dominant compound or constituent thereof.

13. Anarticle of manufacture comprising an improved metal orf'alloy resulting from the purifying and scavenging treatment thereof in a molten state with a lithium-calcium alloy in restricted amounts only sufficient to purify, scavenge and improve the said metal or alloy and insufficient to remain in the finished and treated metal or alloy as a dominant compound or. constituent thereof.

7 14.. An article of manufacture comprising an improved metal or alloy containing a trace of lithium-alkali alloy, remaining in said metal and alloy from thetreatmcnt thereof in a molten state with said lithium-alkali alloy in restricted amounts only suflicient to purify,

scavenge and improve the said metal or alloy and insufficient to remain in the finished and treated metal or alloy as a dominant compound or constituent thereof. v y

In testimony whereof I have hereunto set my hand. a

HANS OSBORG. 

